A woman places flowers by a cut out image of the ARA San Juan submarine on the fence at the naval base in Mar de Plata, Argentina, Friday, Nov. 24, 2017. The Argentine navy says an explosion occurred near the time and place where the submarine went missing on Nov. 15, leading some family members of the crew to give up hope of a rescue. (AP Photo/Esteban Felix)

The wife of sailor Fernando Villarreal, a crew member of the missing submarine, shows his picture as she prays at the naval base in Mar de Plata, Argentina, Friday, Nov. 24, 2017. The Argentine navy says an explosion occurred near the time and place where the ARA San Juan submarine went missing on Nov. 15, leading some family members of the crew to give up hope of a rescue. (AP Photo/Esteban Felix)

A statue of the Virgin Maria hangs in honor of the crew members of the missing submarine ARA San Juan on the fence at the naval base in Mar de Plata, Argentina, Friday, Nov. 24, 2017. The Argentine navy says an explosion occurred near the time and place where the submarine went missing on Nov. 15, leading some family members of the crew to give up hope of a rescue. (AP Photo/Esteban Felix)

This undated photo released by Luis Tagliapietra shows his son Alejandro, one of the crew members of the missing ARA San Juan submarine in Argentina. The Argentine navy says an explosion occurred near the time and place where the ARA San Juan submarine went missing on Nov. 15, leading some family members of the crew to give up hope of a rescue. (Luis Tagliapietra via AP)

This undated photo released by Luis Tagliapietra shows his son Alejandro, one of the crew members of the missing ARA San Juan submarine in Argentina. The Argentine navy says an explosion occurred near the time and place where the ARA San Juan submarine went missing on Nov. 15, leading some family members of the crew to give up hope of a rescue. (Luis Tagliapietra via AP)

In this Thursday, Nov. 23, 2017 photo provided by Brazil's Air Force, Brazilian military aid in the search for Argentina's missing submarine as they fly on a mission over the South Atlantic, after leaving a base in Bahia Blanca, Argentina. Argentina’s president said Friday that an international search will continue for a submarine carrying 44 crew members that has been lost in the South Atlantic since Nov. 15 and that the sub’s disappearance will be investigated. (Brazilian Air Force via AP)

In this Thursday, Nov. 23, 2017 photo provided by Brazil's Air Force, Brazilian military aid in the search for Argentina's missing submarine as they fly on a mission over the South Atlantic, after leaving a base in Bahia Blanca, Argentina. Argentina’s president said Friday that an international search will continue for a submarine carrying 44 crew members that has been lost in the South Atlantic for nine days and that the sub’s disappearance will be investigated. (Brazilian Air Force via AP)

A woman places a flag carrying messages in support of crew members of the missing ARA San Juan submarine on the fence at the naval base in Mar de Plata, Argentina, Friday, Nov. 24, 2017. The Argentine navy says an explosion occurred near the time and place where the submarine went missing on Nov. 15, leading some family members of the crew to give up hope of a rescue. (AP Photo/Esteban Felix)

Luis Tagliaprieta, father of sailor Alejandro Tagliaprieta, a crew member from the missing ARA San Juan submarine, speaks with the press at the naval base in Mar de Plata, Argentina, Friday, Nov. 24, 2017. "Hope is the last thing you lose. I'm waiting for a surprise, but I'm not really counting on it," said Tagliapietra. (AP Photo/Esteban Felix)

Argentine President Mauricio Macri, center, walks towards a podium to give a statement at the navy headquarters in Buenos Aires, Argentina, Friday, Nov. 24, 2017. Macri said the international search for a submarine carrying 44 crew members that has been lost in the South Atlantic since Nov. 15 will continue and that the sub's disappearance will be investigated. (AP Photo/Victor R. Caivano)

Argentine President Mauricio Macri gives a statement about the missing submarine at the navy headquarters in Buenos Aires, Argentina, Friday, Nov. 24, 2017. Macri said the international search for a submarine carrying 44 crew members that has been lost in the South Atlantic since Nov. 15 will continue and that the sub's disappearance will be investigated. (AP Photo/Victor R. Caivano)

In this Sept. 27, 2011 photo, workers stand around the ARA San Juan submarine during a ceremony celebrating the first stage of major repairs at the Argentine Industrial Naval Complex (CINAR) in Buenos Aires. President Mauricio Macri said on Friday, Nov. 24, 2017 the international search for the submarine carrying 44 crew members that has been lost in the South Atlantic since Nov. 15 will continue and that the sub's disappearance will be investigated. (AP Photo/Mario Defina)

Friends and family of missing submarine crew members place a flag on the fence of the naval base in Mar de Plata, Argentina, Friday, Nov. 24, 2017. The Argentine navy says an explosion occurred near the time and place where the ARA San Juan submarine went missing on Nov. 15, leading some family members of the crew to give up hope of a rescue. (AP Photo/Esteban Felix)

Relatives and friends of Alejandro Tagliaprieta, a crew member on the missing ARA San Juan submarine, embrace at the navy base in Mar de Plata, Argentina, Friday, Nov. 24, 2017. The Argentine navy says an explosion occurred near the time and place where the ARA San Juan submarine went missing on Nov. 15, leading some family members of the crew to give up hope of a rescue. (AP Photo/Esteban Felix)

Relatives and friends of Alejandro Tagliaprieta, a crew member on the missing ARA San Juan submarine, cry at the naval base where they hung a flag on the fence in Mar de Plata, Argentina, Friday, Nov. 24, 2017. The navy says an explosion occurred near the time and place where the sub went missing on Nov. 15. That's led some to give up hope. (AP Photo/Esteban Felix)

MAR DEL PLATA, Argentina (AP) — Argentina's president said Friday an international search will continue for a submarine carrying 44 crew members that has been lost in the South Atlantic for nine days and that the sub's disappearance will be investigated.

The Argentine navy says an explosion occurred near the time and place where the submarine went missing on Nov. 15 as it was sailing from the extreme southern port of Ushuaia to the coastal city of Mar del Plata. That's led some family members of the crew to give up hope of a rescue. Navy officials and outside experts also worry that even if the sub is intact but submerged, its crew may be running out of oxygen.

"The disappearance and current search of the ARA San Juan submarine has touched all Argentines. It's a difficult moment for all, but obviously, especially for the families of the 44 crew members," President Mauricio Macri said in his first public comments about the missing sub at the navy's headquarters in Buenos Aires.

"I'm here to guarantee you that we will carry on with the search, especially now that we have the support of all the international community."

More than a dozen airplanes and ships have been participating in the multinational search across an area of some 185,000 square miles (480,000 square kilometers), which is roughly the size of Spain.

The Argentine navy said Friday that Russia is sending an Antonov transport aircraft, and a ship in the southern Patagonian port of Comodoro Rivadavia is being adapted to carry a U.S. Navy submarine rescue chamber. They will focus the search efforts on a smaller area where the explosion was recorded.

The ARA San Juan, a German-built diesel-electric TR-1700 class submarine, was commissioned in 1985 and was most recently refitted in 2014.

"No one goes out to sea knowing that they can lose their life," said Ramon Francisco Escobar, who was part of the crew that first brought the sub from Germany to Argentina in 1985. "It was a reliable submarine."

The sub was originally scheduled to arrive Monday to a navy base in Mar del Plata, about 250 miles (400 kilometers) southeast of Buenos Aires. Local residents prayed for the crew's return during a religious ceremony and later sang Argentina's national anthem outside the base Friday. Some relatives of the crew who have gathered there fear that their loved ones will no longer be rescued.

"Hope is the last thing you lose. I'm waiting for a surprise, but I'm not really counting on it," Luis Tagliapietra, father of 27-year-old crew member Alejandro Damian Tagliapietra, told The Associated Press.

"You go from denial to suffering, from optimism to pessimism," he said, holding back tears. When he found out about the explosion from his son's direct superior, he was told that there was a possibility there were no survivors.

"I asked them if they were all dead, and he said: 'Yes.'"

Some family members have denounced the navy's response to the disappearance and the condition of the 30-year-old vessel.

Although Macri said that it's not the time to point fingers at anyone, he promised a probe of the sub's disappearance.

"This demands a serious, deep investigation," Macri said. "We need to understand how a submarine that had undergone a midlife refit, and that was in perfect conditions to sail, suffered this explosion."